'''Ludwik Lejzer Zamenhof''' (, – ),
usually credited as '''L. L. Zamenhof''', was a Polish physician, inventor, and writer. He is most widely known for creating Esperanto
, the most successful constructed language
in the world.
He grew up fascinated by the idea of a world without war and believed that this could happen with the help of a new international auxiliary language
, which he first developed in 1873 while still in school.